Okay TMI question ladies!!!

Okay TMI question ladies!!!

Early period or implantation bleeding??

Okay so my periods since having my girl have been trying to even out, first one was 2.5 months pp, then 5 months, then 7 months, then 7.5 months (was really 21 days from start of last period), then 8.5 months...I assumed they were coming back to being once a month, now I am 18 days past the first day of my last period and I just saw some light spotting, it was brownish, I was trying to go #2 and then it was a little pinker/red, then went back very light brownish....checked a bit later and barely anything. I should mention we had unprotected sex 4 days ago, and it had been a while and he said he wasn't sure if he orgasmed a little or not, it was a mild feeling but he may have....(sorry tmi but he masterbates a lot cuz we don't get to be intimate very often LOL).....With my 9 month old I had implantation bleeding for a like two days, it was light pink the first day then light brown like this the next day, and I had mild cramping like a period coming but obviously it never did. I am having some mild cramping like that now...

I know it's not an exact science here, but opinions??? Implantation bleeding or a fucked up period???